In answers and comments to What does it mean when a software is called open-source for US-release only? I found out that when NASA uses the term "open source" it does not mean open to everyone! Software can still have export restrictions beyond specified individuals or companies within the US, and still be called "open source" by NASA.

I keep seeing GMAT mentioned in questions and answers in this SE site. I went to the GMAT website and saw two links at the bottom:

This software is released under the terms and conditions of the NASA Open Source Agreement (NOSA) Version 1.1 or later. General Mission Analysis Tool (GMAT) NOSA

Both contain paragraph J:

J. Notwithstanding any provisions contained herein, Recipient is hereby put on notice that export of any goods or technical data from the United States may require some form of export license from the U.S. Government. Failure to obtain necessary export licenses may result in criminal liability under U.S. laws. Government Agency neither represents that a license shall not be required nor that, if required, it shall be issued. Nothing granted herein provides any such export license.

So far I haven't found a clear statement if GMAT is available to everyone, or if you need to go through their application and screening procedure before getting a copy of an executable, or a source-code version of GMAT.

Could someone help me find the answer to "How open is NASA's "open source" GMAT software?"


  • $\begingroup$ I have found this in Github: github.com/rockstorm101/GMAT. If I'm not wrong, here you can find source codes for GMAT. $\endgroup$ Aug 16, 2018 at 7:37
  • $\begingroup$ @AlexJohnson the description certainly looks promising. For an answer to my question, it would be better to have information directly from NASA that this is okay. From your link these is no way to know for sure if this is not an unapproved or unlicensed copy. $\endgroup$
    – uhoh
    Aug 16, 2018 at 7:43
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    $\begingroup$ I found out that it is not the official GMAT repository: as the rockstorm himself writes in README file (at github.com/rockstorm101/GMAT), "Therefore this is an unofficial repository of GMAT R2015a. It simply gathers all the necessary files from the official repository, adds a compile-and-install script and details the installation process.". Didn't notice before, I apologise. But at this readme file also the link to the source code is provided: sourceforge.net/p/gmat/git/ci/GMAT-R2018a/tree. Is it what you were looking for? $\endgroup$ Aug 16, 2018 at 8:10
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    $\begingroup$ GMAT is on SourceForge.net. Other NASA open source is on github/nasa. Yet other NASA open source can be obtained only by request from NASA. Anyone anywhere in the world with an unfettered internet connection can access SourceForge or GitHub. Everything NASA has placed on those two sites has already been exported to the world by NASA itself. Paragraph J of NASA's open source agreement pertains to the stuff that NASA deems open source but that you can't find on SourceForge or GitHub. $\endgroup$ Aug 16, 2018 at 11:29
  • $\begingroup$ @DavidHammen Thanks! I don't use SorceForge.net (due to my allergy to curly braces). Did NASA officially put it there? That's probably the factor that would serve as an answer to the question. If they did, consider writing an answer I can accept? $\endgroup$
    – uhoh
    Aug 16, 2018 at 12:07

1 Answer 1


GMAT has been released under the Apache license since R2013a, so I'd say it's about as wide open as you can get.


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